The present invention relates to an ultrasonic actuator which includes a piezoelectric element.
Conventionally, an ultrasonic actuator is known which includes a piezoelectric element (electromechanical conversion element) for use in various electric devices and other types of devices (e.g., see Patent Document 1). This piezoelectric element is formed by alternately stacking piezoelectric bodies and electrodes. In the ultrasonic actuator, voltages are applied to the electrodes to cause the piezoelectric element to vibrate, whereby a movable element is moved.
Another ultrasonic actuator is known in which the piezoelectric element is energized to generate the first vertical vibration in a driving direction and the second bending direction in a direction perpendicular to the driving direction so that a vibrator provided in the piezoelectric element make an orbital movement which is a synthesis of the vertical vibration and the bending vibration, whereby a movable element is moved (e.g., see Patent Document 2).
To apply voltages to the electrodes of the piezoelectric element, the electrodes are connected to conductive members.
Patent Document 1: Japanese Laid-Open PCT National-Phase Publication No. 2003-501988
Patent Document 2: Japanese Laid-Open Patent Publication No. 2000-295876